How to move or resize to fit to certain plane?
I think you should be able to do it with Snap to Mesh functionality in both Object and Edit mode (shift+tab), no need for any "work planes".

Here is the wiki page with a more precise description of the function:
https://wiki.blender.org/index.php/Doc:2.4/Manual/3D_interaction/Transform_Control/Snap_to_Mesh